sorry I am a little late in responding. We have been underway and with patchy internet. We have the fixed prop(autoprop as a spare, set up preferred by previous owner which I have not felt compelled to change) and will generate useful power starting between 4-5kts. At hull speed, say 7.5-9.0 kts the alternator produces more power than we can use. The regulator is set to 27.5 volts and will float the batteries at that voltage.
I don't have an ammeter on the alternator output, but If the battery needs charge the highest I have seen gling in is 15 amps. This of course would be in addition to running loads which vary. We have one bench freezer, the galley frig and a portable 24V chest frig. Underway we have a Raymarine Es78 chart plotter, Furuno 1623 radar, VHF and AIS running at all times. Oh and the Igloo Ice Maker!
SV Annie SM 37
Charlotte Amalie, St Thomas USVI